

The concept of “End to End Encryption” (E2EE) is that one end encrypts the data, it passes through transport, and the only person who can read the decrypted data is the intended receiver.
In the case of WhatsApp, this should mean:
- Your phone (WhatsApp app) encrypts a message
- Your phone sends the encrypted (“unreadable”) message to Facebook
- Facebook sends the message to the intended receiver
- The receiver decrypts the message
The whole “Meta AI summaries” thing has to run on their servers. Large language models small enough to fit on a phone don’t produce sensible output yet, and your phones battery would drain very quickly. Since each message is (supposed to be) encrypted with different keys, no human nor computer can make sense of the encrypted data without the keys to decrypt it. For their servers to provide a “summary of your chats”, they have to be able to read the content of the messages. Thus proving that the whole “end to end encryption” in WhatsApp is either false, or made entirely useless with them sending all messages to themselves without E2EE.
The only proof that would invalidate this is evidence of the LLM running locally on device. Even then, the way some of WhatsApp’s services work (like notifications, WhatsApp Web) creates some serious doubt on the “E2EE” claim.
It is absolutely essential that any communications platform claiming “E2EE” proves this by making the client-side code (the stuff running on your device) fully open source. A proprietary app, like WhatsApp, by definition makes it harder to fully understand its inner workings, and thus fully verify the E2EE claim.
There is no justification. The “Ends” in E2EE mean the initial sender, and intended recipient. The “transport” should have zero insight into the content. Encrypting a message to the servers is standard even for “non-private” messaging services, it’s usually done with SSL (part of HTTPS).
Lets compare it to traditional mail. If you send something, the postal company can always just open your mail and read it. With computers, we have black magic (E2EE) that physically prevents the postal company from doing that. In this hypothetical, Facebook (owner of WhatsApp) is the company that provides you with the pen and paper (the app), and is a postal company (their servers). They promise that the black magic on the paper prevents them from reading what you wrote, but then they clearly read the content of your letter to send you a summary of the conversation.
Mid-message quick edit: They could’ve also done something to the pen (other parts of the app) to have it tell them what you wrote. This would mean the black magic (E2EE) is applied, but is completely useless. (End of edit)
If the process for making the pen and paper (the app) was publicly known (open source), you could make your own, and be sure the black magic (E2EE) is applied properly. That way you can be certain the postal company (servers) can’t read your letter, only the recipient can.
If the postal company gives you the pen and paper without telling you how to make it, it’s nearly impossible to tell if the black magic was applied properly.